enzyme-degradable polymer includes natural products and synthetic materials, which can be widely used in the fields of the drug release, clinical diagnosis, biological detection analysis and other fields.
General, the detection of the enzyme is realized through fluorescent, light or color changing, wherein, the most common method is coupling the enzyme substrate (short peptides or other small molecules substrate) with a single functional or bifunctional fluorescent dyes, luminescent substrate; first, the fluorescent dye, luminescent substrate is set to a latent state by electron-attracting effect, while these short peptides or other small molecules substrate are used as probe for detecting the enzyme. When the presence of the corresponding enzyme, the enzyme will cut off the part of its substrate first, to thereby remove the electron-withdrawing effect of the fluorescent dye, luminescent substrate. Finally, it is possible to directly detect the signal, such as light; or applying an external signal source, such as laser and later read-out the signal (fluorescence). This kind of enzyme detect substrate, an enzyme catalyze one time can only activate one molecule (monofunctional latent state fluorescent or luminescent labled materials) or ½ molecules (bifunctional latent state fluorescent or luminescent labled materials) of signal units. Therefore, this kind of enzyme detect substrate, the sensitivity of detection is lower.
Histone deacetylases (HDACs) are a class of proteases playing an important role in chromosome structure modification and regulation of gene expression. In cancer cells, the over-expression of HDACs results acetylation enhanced, thereby increasing the attraction between the DNA and histones by recovering histone positive charge, and to make the relaxed nucleosome become very close, this is not helpful for the specific gene expression, including several tumor suppressor gene. But, for the absence of the convenient tools for analysing HDAC, the screen of complex substance which can suppress HDAC is more difficult.